Method Of Protecting Teeth Against Erosion

ABSTRACT

Disclosed are methods of treating and protecting teeth against erosion by use of oral compositions comprising polymeric mineral surface active agents, metal ions such as stannous and zinc and combinations thereof. The present methods provide improved resistance of teeth to erosive demineralization or dissolution and prevention of tooth damage by subsequent exposure of teeth to erosive chemicals such as acidic foods and beverages.

FIELD OF THE INVENTION

The present invention relates to methods of treating and protectingteeth against erosion by use of oral compositions comprising polymericmineral surface active agents, metal ions such as stannous and zinc andcombinations thereof. The present methods provide improved resistance ofteeth to erosive demineralization or dissolution and prevention of toothdamage by subsequent exposure of teeth to erosive chemicals such asacidic foods and beverages.

BACKGROUND OF THE INVENTION

Oral care products such as toothpastes are routinely used by consumersas part of their oral care hygiene regimens. It is well known that oralcare products can provide both therapeutic and cosmetic hygiene benefitsto consumers. Therapeutic benefits include caries prevention which istypically delivered through the use of various fluoride salts;gingivitis prevention by the use of an antimicrobial agent such astriclosan, stannous fluoride, zinc citrate or essential oils; orhypersensitivity control through the use of ingredients such asstrontium chloride or potassium nitrate. Cosmetic benefits provided byoral products include the control of plaque and calculus formation,removal and prevention of tooth stain, tooth whitening, breathfreshening, and overall improvements in mouth feel impression which canbe broadly characterized as mouth feel aesthetics.

In addition to the above mentioned therapeutic and cosmetic benefitsoral care products can be used as a vehicle to deliver other benefits.The present inventors have surprisingly discovered additional importantbenefits of oral compositions comprising certain chemical agents thathave affinity for the tooth surface. These agents either bind to thetooth surface or form insoluble compounds or complexes on the toothsurface, thereby forming a protective film or coating on the toothsurface. As a result of these protective coatings, teeth are providedwith remarkable resistance and protection against dental erosionchallenges for extended periods of time following use of the compositioncontaining these agents.

Dental erosion is a permanent loss of tooth substance from the surfaceby the action of chemicals, such as harsh abrasives and acids, asopposed to subsurface demineralization or caries caused by bacterialaction. Dental erosion is a condition that does not involve plaquebacteria and is therefore distinct from dental caries, which is adisease caused by acids generated by plaque bacteria. Dental erosion maybe caused by extrinsic or intrinsic factors. Extrinsic erosion is theresult of oral consumption of dietary acids such as acidic beverages orfruit juices and environmental factors such as exposure to airbornecontamination or acidic water in swimming pools. Intrinsic erosion iscaused for example by endogeous acids produced in the stomach and whichcontact the teeth during the processes of vomiting, regurgitation orreflux. The main cause of regurgitation and induced vomiting are eatingdisorder conditions such as nervous vomiting, anorexia or bulimia (Moss,1998, Int. Den. J., 48, 529).

The incidence and severity of dental erosion is on the rise with theincrease in the consumption of acidic beverages and juices. The pH andtitratable acidity of acidic beverages have been identified as the maincausative agents in the initiation and progression of dental erosion(Lussi, 1995, Caries Res. 29, 349). Thus methods have been disclosed tomodify acidic food and beverage products in order to prevent theirerosive effect on teeth. See for example, U.S. Pat. No. 5,108,761 and WO01/52796 both assigned to The Procter & Gamble Company; U.S. Pat. Nos.6,383,473; 6,319,490; WO 01/72144; and WO 00/13531 all assigned toSmithKline Beecham; Calif. 1018393 assigned to General FoodsCorporation; U.S. Pat. No. 3,471613 and BE 638645, both assigned toColonial Sugar Refining Co; and U.S. Pat. No. 4,853,237 assigned toSinebrychoff Oy. In addition there have been disclosures of oral carecompositions comprising agents indicated to provide teeth withantierosion or acid resistance benefits. See for example, JP2001/158725; US 4,363,794 and U.S. Pat. No. 4,335,102 all assigned toLion Corporation; U.S. Pat. No. 5,130,123 assigned to The University ofMelbourne; WO 99/08550 and WO 97/30601 both assigned to SmithKlineBeecham; U.S. Pat. No. 3,914,404, assigned to Dow Chemical Co.; and U.S.Pat. No. 3,105,798, assigned to The Procter & Gamble Co.

Because of the nearly epidemic incidence of dental erosion problems,there is a continuing need for improved products that provide immediateas well as sustained protection against dental erosion challenges. Thepresent inventors have discovered that such immediate and sustainedprotection can be provided by the use of oral care products comprisingpolymeric mineral surface active agents such as polyphosphates that bindto teeth, or metal ions such as stannous, zinc or copper that forminsoluble compounds that deposit onto teeth, and combinations thereof.The polymeric coating or insoluble precipitate deposited onto teeth actas a protective layer that prevents erosive chemicals from contactingthe tooth surface and etching away tooth hard tissue.

SUMMARY OF THE INVENTION

The present invention relates to a method of protecting a subject'steeth from erosion caused by the action of chemicals, such as harshabrasives and acids, by the use of an oral care composition comprising apolymeric mineral surface-active agent selected from the groupconsisting of condensed phosphorylated polymers; polyphosphonates;polycarboxylates and carboxy-substituted polymers; copolymers ofphosphate- or phosphonate-containing monomers or polymers withethylenically unsaturated monomers, amino acids, or with other polymersselected from proteins, polypeptides, polysaccharides, poly(acrylate),poly(acrylamide), poly(methacrylate), poly(ethacrylate),poly(hydroxyalkylmethacrylate), poly(vinyl alcohol), poly(maleicanhydride), poly(maleate) poly(amide), poly(ethylene amine),poly(ethylene glycol), poly(propylene glycol), poly(vinyl acetate) orpoly(vinyl benzyl chloride); and mixtures thereof, wherein saidpolymeric mineral surface-active agent is substantive to teeth anddeposits a layer that protects teeth from erosive damage.Advantageously, the antierosion protection is provided immediately afteruse of the present compositions and maintained for prolonged periods oftime for at least about one hour thereafter. Also useful as antierosionagents are metal ions selected from stannous, zinc and copper, whichdeposit onto teeth a highly insoluble film or precipitate of compoundsor complexes formed from the reaction of the metal ions with otheringredients of the oral composition and/or components of the enamelsurface.

These and other features, aspects, and advantages of the presentinvention will become evident to those skilled in the art from thedetailed description which follows.

DETAILED DESCRIPTION OF THE INVENTION

While the specification concludes with claims which particularly pointout and distinctly claim the invention, it is believed the presentinvention will be better understood from the following description.

-   -   All documents cited are, in relevant part, incorporated herein        by reference; the citation of any document is not to be        construed as an admission that it is prior art with respect to        the present invention.

All percentages and ratios used herein are by weight of the specificoral composition and not of the overall oral formulation that isdelivered, unless otherwise specified. All measurements are made at 25°C., unless otherwise specified.

Herein, “comprising” means that other steps and other ingredients whichdo not affect the end result can be added. This term encompasses theterms “consisting of” and “consisting essentially of”.

By “oral composition” is meant a product which in the ordinary course ofusage, is not intentionally swallowed for purposes of systemicadministration of particular therapeutic agents, but is rather retainedin the oral cavity for a time sufficient to contact substantially all ofthe dental surfaces and/or oral tissues for purposes of oral activity.The oral composition of the present invention may be in the form of atoothpaste, dentifrice, tooth powder, topical oral gel, mouthrinse,denture product, mouthspray, lozenge, oral tablet, or chewing gum.

-   -   The term “dentifrice”, as used herein, means paste, gel, or        liquid formulations unless otherwise specified. The dentifrice        composition may be a single phase composition or may be a        combination of two or more dentifrice compositions. The        dentifrice composition may be in any desired form, such as deep        striped, surface striped, multilayered, having the gel        surrounding the paste, or any combination thereof. Each        dentifrice composition in a dentifrice comprising two or more        separate dentifrice compositions may be contained in a        physically separated compartment of a dispenser and dispensed        side-by-side.

The term “dispenser”, as used herein, means any pump, tube, or containersuitable for dispensing the oral care compositions.

The term “teeth”, as used herein, refers to natural teeth as well asartificial teeth or dental prosthesis.

The term “orally acceptable carrier” as used herein means any safe andeffective materials for use in the compositions of the presentinvention. Such materials include fluoride ion sources, additionalanticalculus agents, buffers, abrasive polishing materials, peroxidesources, alkali metal bicarbonate salts, thickening materials,humectants, water, surfactants, titanium dioxide, flavor system,sweetening agents, xylitol, coloring agents, and mixtures thereof.

Herein, the terms “tartar” and “calculus” are used interchangeably andrefer to mineralized dental plaque deposits.

-   -   The present invention relates to use of oral compositions        containing particular polymeric mineral surface active agents,        metal ions selected from stannous, zinc and copper, and        combinations thereof, which provide effective protection against        dental erosion derived from the deposition on the tooth surface        of a protective layer or coating comprised of the polymeric        mineral surface active agent and/or a highly insoluble film or        precipitate of compounds or complexes formed from the reaction        of the metal ions with other ingredients of the oral composition        and/or components of the enamel surface. Such insoluble        compounds include the metal hydroxide, oxide, phosphate,        fluorophosphate, oxyfluoride and the like. hi particular, these        agents provide physical (surface coverage) and/or chemical        (insoluble compounds deposited on surface) control of tooth        surface characteristics including modification of surface        hydrophilic and hydrophobic properties and resistance to acid        attack. Importantly, the protective effect is provided        immediately after use of the oral composition and lasts for at        least about an hour or longer.

The polymeric mineral surface active agents include any agent which willproduce the desired surface protection effects. These agents alsoprovide desired surface conditioning effects including: 1) the effectivedesorption of portions of undesirable adsorbed pellicle proteins, inparticular those associated with tooth stain binding, calculusdevelopment and attraction of undesirable microbial species; 2) creatinga hydrophilic tooth surface immediately after treatment; and 3)maintaining surface conditioning effects and control of pellicle filmfor extended periods following product use, including post brushing andthroughout more extended periods. The effect of creating an increasedhydrophilic surface can be measured in terms of a relative decrease inwater contact angles. The hydrophilic surface, importantly, ismaintained on the tooth surface for an extended period after using theproduct, e.g., tooth brushing. Many of these polymeric agents are alsoknown or expected to provide tartar control or antistain/whitening orsurface conditioning activities when applied in oral compositions, henceproviding multiple clinical actions in improving the appearance ofteeth, improving the tactile impression to consumers and maintaining thestructure of the teeth.

The polymeric mineral surface active agents include any agent which willhave a strong affinity for enamel surface, deposit a polymer layer orcoating on the enamel surface and produce the desired surface protectioneffects. Suitable examples of such polymers are polyelectrolytes such ascondensed phosphorylated polymers; polyphosphonates; copolymers ofphosphate- or phosphonate-containing monomers or polymers with othermonomers such as ethylenically unsaturated monomers and amino acids orwith other polymers such as proteins, polypeptides, polysaccharides,poly(acrylate), poly(acrylamide), poly(methacrylate), poly(ethacrylate),poly(hydroxyalkylmethacrylate), poly(vinyl alcohol), poly(maleicanhydride), poly(maleate) poly(amide), poly(ethylene amine),poly(ethylene glycol), poly(propylene glycol), poly(vinyl acetate) andpoly(vinyl benzyl chloride); polycarboxylates and carboxy-substitutedpolymers; and mixtures thereof. Suitable polymeric mineral surfaceactive agents include the carboxy-substituted alcohol polymers describedin U.S. Pat. Nos. 5,292,501; 5,213,789, 5,093,170; 5,009,882; and4,939,284; all to Degenhardt et al.; the diphosphonate-derivatizedpolymers in U.S. Pat. No. 5,011,913 to Benedict et al.; and thesynthetic anionic polymers including polyacrylates and copolymers ofmaleic anhydride or acid and methyl vinyl ether (e.g., Gantrez), asdescribed, for example, in U.S. Pat. No. 4,627,977, to Gaffar et al. Apreferred polymer is diphosphonate modified polyacrylic acid. Polymerswith activity must have sufficient surface binding propensity to desorbpellicle proteins and remain affixed to enamel surfaces. For toothsurfaces, polymers with end or side chain phosphate or phosphonatefunctions may both be preferred although other polymers with mineralbinding activity may prove effective depending upon adsorption affinity.

Additional examples of suitable phosphonate containing polymeric mineralsurface active agents include the geminal diphosphonate polymersdisclosed as anticalculus agents in U.S. Pat. No. 4,877,603 toDegenhardt et al; phosphonate group containing copolymers disclosed inU.S. Pat. No. 4,749,758 to Dursch et al. and in GB 1,290,724 (bothassigned to Hoechst) suitable for use in detergent and cleaningcompositions; and the copolymers and cotelomers disclosed as useful forapplications including scale and corrosion inhibition, coatings, cementsand ion-exchange resins in U.S. Pat. No. 5,980,776 to Zakikhani et al.and U.S. Pat. No. 6,071,434 to Davis et al. Preferred polymers includethe water-soluble copolymers of vinylphosphonic acid and acrylic acidand salts thereof disclosed in GB 1,290,724 wherein the copolymerscontain from about 10% to about 90% by weight vinylphosphonic acid andfrom about 90% to about 10% by weight acrylic acid, more particularlywherein the copolymers have a weight ratio of vinylphosphonic acid toacrylic acid of 70% vinylphosphonic acid to 30% acrylic acid; 50%vinylphosphonic acid to 50% acrylic acid; or 30% vinylphosphonic acid to70% acrylic acid. Other preferred polymers include the water solublepolymers disclosed by Zakikhani and Davis prepared by copolymerizingdiphosphonate or polyphosphonate monomers having one or more unsaturatedC═C bonds (e.g., vinylidene-1,1-diphosphonic acid and2-(hydroxyphosphinyl)ethylidene-1,1-diphosphonic acid), with at leastone further compound having unsatd. C═C bonds (e.g., acrylate andmethacrylate monomers), such as those having the following structure:

1. Co-Telomer of Acrylic Acid and2-(hydroxyphosphinyl)ethylidene-1,1-diphosphonic Acid with Structure:

2. Co-Polymer of Acrylic Acid and Vinyldiphosphonic Acid with Structure:

Suitable polymers include the diphosphonate/acrylate polymers suppliedby Rhodia under the designation ITC 1087 (Average MW 3000-60,000) andPolymer 1154 (Average MW 6000-55,000).

A preferred polymeric mineral surface active agent will be stable withother components of the oral care composition such as ionic fluoride andmetal ions and will not hydrolyze in high water content formulations,thus permitting a simple single phase dentifrice or mouthrinseformulation. If the polymeric mineral surface active agent does not havethese stability properties, one option is a dual phase formulation withthe polymeric mineral surface active agent separated from the fluorideor other incompatible component. Another option is to formulate anon-aqueous, essentially non-aqueous or limited water compositions tominimize reaction between the polymeric mineral surface active agent andother components.

A preferred polymeric mineral surface active agent is a polyphosphate. Apolyphosphate is generally understood to consist of two or morephosphate molecules arranged primarily in a linear configuration,although some cyclic derivatives may be present. Although pyrophosphatesare technically polyphosphates, the polyphosphates desired are thosehaving around three or more phosphate molecules so that surfaceadsorption at effective concentrations produces sufficient non -boundphosphate functions, which enhance the anionic surface charge as well ashydrophilic character of the surfaces. The pyrophosphates are discussedseparately under additional anticalculus agents. The inorganicpolyphosphate salts desired include tripolyphosphate, tetrapolyphosphateand hexametaphosphate, among others. Polyphosphates larger thantetrapolyphosphate usually occur as amorphous glassy materials.Preferred in this invention are the linear “glassy” polyphosphateshaving the formula:

XO(XPO₃)_(n)X

wherein X is sodium or potassium and n averages from about 3 to about125. Preferred polyphosphates are those having n averaging from about 6to about 21, such as those manufactured by FMC Corporation andcommercially known as Sodaphos (n˜6), Hexaphos (n˜13), and Glass H(n˜21). A particularly preferred polyphosphate has n averaging about 21such as Glass H. These polyphosphates may be used alone or in acombination thereof.

Oral compositions which comprise polyphosphates are disclosed in e.g.,U.S. Pat. Nos. 5,939,052, 6,190,644, 6,187,295, and 6,350,436, allassigned to The Procter & Gamble Co. In these compositions, thepolyphosphates are disclosed to provide benefits including tartarinhibition and reducing aesthetic negatives such as astringency andstaining caused by other actives such as stannous. The use ofpolyphosphates for the prevention of dental erosion is not disclosed.The polyphosphate sources are also described in more detail inKirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, Volume18, Wiley-Interscience Publishers (1996).

The amount of polymeric mineral surface agent required is an effectiveamount to provide the protection from erosion due to acid or abrasivechallenges, the protection lasting for at least about an hour after useof the composition. An effective amount of a polymeric mineral surfaceactive agent will typically be from about 1% to about 35%, preferablyfrom about 2% to about 30%, more preferably from about 5% to about 25%,and most preferably from about 6% to about 20%, by weight of the totaloral composition.

The metal ions suitable for use in the present invention have strongaffinity for enamel surface and include stannous, copper and zinc ions.These ions provide surface protection effects by reacting with toothsurface ions and/or other components of the composition to producehighly insoluble compounds on the surface. Additionally, these metalions undergo oxidation and hydrolysis under salivary pH conditions andproduce insoluble deposits on tooth surfaces.

The present compositions may comprise a metal ion source that providesstannous ions, zinc ions, copper ions, or mixtures thereof. The metalion source can be a soluble or a sparingly soluble compound of stannous,zinc, or copper with inorganic or organic counter ions. Examples includethe fluoride, chloride, chlorofluoride, acetate, hexafluorozirconate,sulfate, tartrate, gluconate, citrate, malate, glycinate, pyrophosphate,metaphosphate, oxalate, phosphate, carbonate salts and oxides ofstannous, zinc, and copper.

Stannous, zinc and copper ions are derived from the metal ion source(s)found in the dentifrice composition in an effective amount to providethe antierosion benefit or other benefits. Stannous, zinc and copperions have been found to help in the reduction of gingivitis, plaque,sensitivity, and improved breath benefits. An effective amount isdefined as from at least about 500 ppm to about 20,000 ppm metal ion ofthe total composition, preferably from about 2,000 ppm to about 15,000ppm. More preferably, metal ions are present in an amount from about3,000 ppm to about 13,000 ppm and even more preferably from about 5,000ppm to about 10,000 ppm. This is the total amount of metal ions(stannous, zinc, copper and mixtures thereof) that is present in thecompositions for delivery to the tooth surface.

Dentifrices containing stannous salts, particularly stannous fluorideand stannous chloride, are described in U.S. Pat. No. 5,004,597 toMajeti et al.. Other descriptions of stannous salts are found in U.S.Pat. No. 5,578,293 issued to Prencipe et al. and in U.S. Pat. No.5,281,410 issued to Lukacovic et al.. In addition to the stannous ionsource, other ingredients needed to stabilize the stannous may also beincluded, such as the ingredients described in Majeti et al. andPrencipe et al. However, it has been found that the antierosion benefitsof stannous may be negatively affected by certain stabilizing agents,such as phytic acid, ethylenediaminetetraacetic acid (EDTA) and saltsthereof. The present compositions are thus preferably essentially freeof phytates and ethylenediaminetetraacetates. By “essentially free” ismeant that the compositions have no more than 0.01% by weight of theseagents.

The preferred stannous salts are stannous fluoride and stannous chloridedihydrate. Other suitable stannous salts include stannous acetate,stannous tartrate and sodium stannous citrate. Examples of suitable zincion sources are zinc oxide, zinc sulfate, zinc chloride, zinc citrate,zinc lactate, zinc gluconate, zinc malate, zinc tartrate, zinccarbonate, zinc phosphate, and other salts listed in U.S. Pat. No4,022,880. Zinc citrate and zinc lactate are particularly preferred.Examples of suitable copper ion sources are listed in U.S. Pat. No.5,534,243. The combined metal ion source(s) will be present in an amountof from about 0.1% to about 11%, by weight of the final composition.Preferably, the metal ion sources are present in an amount of from about0.5 to about 7%, more preferably from about 1% to about 5%. Preferably,the stannous salts may be present in an amount of from about 0.1 toabout 7%, more preferably from about 1% to about 5%, and most preferablyfrom about 1.5% to about 3% by weight of the total composition. Theamount of zinc or copper salts used in the present invention ranges fromabout 0.01 to about 5%, preferably from about 0.05 to about 4% and morepreferably from about 0.1 to about 3.0%.

In preparing the present compositions, it is desirable to add one ormore aqueous carriers to the compositions. Such materials are well knownin the art and are readily chosen by one skilled in the art based on thephysical and aesthetic properties desired for the compositions beingprepared. These carriers may be included at levels which do notinterfere or prohibit the surface effects of the polymeric mineralsurface active agent. The amount of polymeric mineral surface activeagent may be increased to account for the additional carriers. Aqueouscarriers typically comprise from about 50% to about 99%, preferably fromabout 70% to about 98%, and more preferably from about 80% to about 95%,by weight of the oral composition.

The oral composition of the present invention may incorporate a solublefluoride source capable of providing free fluoride ions. The fluorideion source may preferably be in a separate phase than the polymericsurface active agent to aid in stability. Preferred soluble fluoride ionsources include sodium fluoride, stannous fluoride, indium fluoride,amine fluoride and sodium monofluorophosphate. Sodium fluoride andstannous fluoride the most preferred soluble fluoride ion source.Stannous fluoride and methods of stabilization are described in U.S.Pat. No. 5,004,597 issued to Majeti et al. and in U.S. Pat. No.5,578,293 issued to Prencipe et al., in addition to other sources Norriset al., U.S. Pat. No. 2,946,725, issued Jul. 26, 1960, and Widder etal., U.S. Pat. No. 3,678,154 issued Jul. 18, 1972, disclose suchfluoride ion sources as well as others.

The present compositions contain a soluble fluoride ion source capableof providing from about 50 ppm to about 3500 ppm, and preferably fromabout 500 ppm to about 3000 ppm of free fluoride ions.

The present compositions may contain a buffering agent. Bufferingagents, as used herein, refer to agents that can be used to adjust thepH of the compositions to a range of about pH 4 to about pH 10. The oralcomposition containing a polymeric mineral surface active agent willtypically have a slurry pH of from about 4 to about 10, preferably fromabout 4.5 to about 8, and more preferably from about 5.5 to about 7. Thebuffering agents include alkali metal hydroxides, carbonates,sesquicarbonates, borates, silicates, phosphates, imidazole, andmixtures thereof. Specific buffering agents include monosodiumphosphate, trisodium phosphate, sodium hydroxide, potassium hydroxide,alkali metal carbonate salts, sodium carbonate, imidazole, pyrophosphatesalts, citric acid, and sodium citrate. Buffering agents are used at alevel of from about 0.1% to about 30%, preferably from about 1% to about10%, and more preferably from about 1.5% to about 3%, by weight of thepresent composition.

Optional agents that may be used in combination with the polymericmineral surface active agent include such materials known to beeffective in reducing calcium phosphate mineral deposition related tocalculus formation. Pyrophosphate salts may be used in the presentinvention as anticalculus agents or as buffering agents, as long of thesurface conditioning effects of the polymeric surface active agent isnot eliminated. The pyrophosphate salts useful in the presentcompositions include the dialkali metal pyrophosphate salts, tetraalkali metal pyrophosphate salts, and mixtures thereof. Disodiumdihydrogen pyrophosphate (Na₂H₂P₂O₇), tetrasodium pyrophosphate(Na₄P₂O₇), and tetrapotassium pyrophosphate (K₄P₂O₇) in their unhydratedas well as hydrated forms are the preferred species. In compositions ofthe present invention, the pyrophosphate salt may be present in one ofthree ways: predominately dissolved, predominately undissolved, or amixture of dissolved and undissolved pyrophosphate.

Compositions comprising predominately dissolved pyrophosphate refer tocompositions where at least one pyrophosphate ion source is in an amountsufficient to provide at least about 1.0% free pyrophosphate ions. Theamount of free pyrophosphate ions may be from about 1% to about 15%,preferably from about 1.5% to about 10%, and most preferably from about2% to about 6%, by weight of the composition. Free pyrophosphate ionsmay be present in a variety of protonated states depending on the pH ofthe composition.

Compositions comprising predominately undissolved pyrophosphate refer tocompositions containing no more than about 20% of the totalpyrophosphate salt dissolved in the composition, preferably less thanabout 10% of the total pyrophosphate dissolved in the composition.Tetrasodium pyrophosphate salt is the preferred pyrophosphate salt inthese compositions. Tetrasodium pyrophosphate may be the anhydrous saltform or the decahydrate form, or any other species stable in solid formin the dentifrice compositions. The salt is in its solid particle form,which may be its crystalline and/or amorphous state, with the particlesize of the salt preferably being small enough to be aestheticallyacceptable and readily soluble during use. The amount of pyrophosphatesalt useful in making these compositions is any tartar control effectiveamount, and is generally from about 1.5% to about 15%, preferably fromabout 2% to about 10%, and most preferably from about 2.5% to about 8%,by weight of the composition. Some or all of the tetrasodiumpyrophosphate may be undissolved in the product and present astetrasodium pyrophosphate particles. Pyrophosphate ions in differentprotonated states (e.g., HP₂O₇ ⁻³) may also exist depending upon the pHof the composition and if part of the tetrasodium pyrophosphate isdissolved.

Compositions may also comprise a mixture of dissolved and undissolvedpyrophosphate salts. Any of the above mentioned pyrophosphate salts maybe used.

The pyrophosphate salts are described in more detail in Kirk-OthmerEncyclopedia of Chemical Technology, Third Edition, Volume 17,Wiley-Interscience Publishers (1982). Additional anticalculus agentsinclude other materials known to be effective in reducing calciumphosphate mineral deposition related to calculus formation. Agentsincluded are synthetic anionic polymers including polyacrylates andcopolymers of maleic anhydride or acid and methyl vinyl ether (e.g.,Gantrez), as described, for example, in U.S. Pat. No. 4,627,977, toGaffar et al., as well as, e.g., polyamino propane sulfonic acid(AMPS)], zinc citrate trihydrate, diphosphonates (e.g., EHDP; AHP),polypeptides (such as polyaspartic and polyglutamic acids), and mixturesthereof.

An abrasive polishing material may also be included in the oralcompositions. The abrasive polishing material contemplated for use inthe compositions of the present invention can be any material which doesnot excessively abrade dentin. The abrasive polishing material should beformulated in the oral composition so that it does not compromise thestability of any ingredients, such as stannous fluoride. Typicalabrasive polishing materials include silica gels and precipitates;aluminas; phosphates including orthophosphates, polymetaphosphates, andpyrophosphates; and mixtures thereof. Specific examples includedicalcium orthophosphate dihydrate, calcium pyrophosphate, tricalciumphosphate, calcium polymetaphosphate, insoluble sodiumpolymetaphosphate, hydrated alumina, beta calcium pyrophosphate, calciumcarbonate, and resinous abrasive materials such as particulatecondensation products of urea and formaldehyde, and others such asdisclosed by Cooley et al in U.S. Pat. No. 3,070,510, issued Dec. 25,1962. Mixtures of abrasives may also be used.

Silica dental abrasives of various types are preferred because of theirunique benefits of exceptional dental cleaning and polishing performancewithout unduly abrading tooth enamel or dentine. The silica abrasivepolishing materials herein, as well as other abrasives, generally havean average particle size ranging between about 0.1 to about 30 microns,and preferably from about 5 to about 15 microns. The abrasive can beprecipitated silica or silica gels such as the silica xerogels describedin Pader et al., U.S. Pat. No. 3,538,230, issued Mar. 2, 1970, andDiGiulio, U.S. Pat. No. 3,862,307, issued Jan. 21, 1975. Preferred arethe silica xerogels marketed under the trade name “Syloid” by the W. R.Grace & Company, Davison Chemical Division. Also preferred are theprecipitated silica materials such as those marketed by the J. M. HuberCorporation under the trade name, “Zeodent”, particularly the silicacarrying the designation “Zeodent 119”. The types of silica dentalabrasives useful in the toothpastes of the present invention aredescribed in more detail in Wason, U.S. Pat. No. 4,340,583, issued Jul.29, 1982. Silica abrasives are also described in Rice, U.S. Pat. Nos.5,589,160; 5,603,920; 5,651,958; 5,658,553; and 5,716,601. The abrasivein the toothpaste compositions described herein is generally present ata level of from about 6% to about 70% by weight of the composition.Preferably, toothpastes contain from about 10% to about 50% of abrasive,by weight of the dentifrice composition.

The present invention may include a peroxide source in the oralcomposition. The peroxide source is selected from the group consistingof hydrogen peroxide, calcium peroxide, urea peroxide, and mixturesthereof. The preferred peroxide source is calcium peroxide. Thefollowing amounts represent the amount of peroxide raw material,although the peroxide source may contain ingredients other than theperoxide raw material. The present composition may contain from about0.01% to about 10%, preferably from about 0.1% to about 5%, morepreferably from about 0.2% to about 3%, and most preferably from about0.3% to about 0.8% of a peroxide source, by weight of the dentifricecomposition.

The present invention may also include an alkali metal bicarbonate salt.Alkali metal bicarbonate salts are soluble in water and unlessstabilized, tend to release carbon dioxide in an aqueous system. Sodiumbicarbonate, also known as baking soda, is the preferred alkali metalbicarbonate salt. The alkali metal bicarbonate salt also functions as abuffering agent. The present composition may contain from about 0.5% toabout 50%, preferably from about 0.5% to about 30%, more preferably fromabout 2% to about 20%, and most preferably from about 5% to about 18% ofan alkali metal bicarbonate salt, by weight of the dentifricecomposition.

The present invention provides compositions in the form of toothpastes,dentifrices, tooth powder, topical oral gels, mouthrinses, dentureproduct, mouthsprays, lozenges, oral tablets, and chewing gums.Typically these compositions will contain some thickening material orbinders to provide a desirable consistency. Preferred thickening agentsare carboxyvinyl polymers, carrageenan, hydroxyethyl cellulose, andwater soluble salts of cellulose ethers such as sodiumcarboxymethylcellulose and sodium hydroxyethyl cellulose. Natural gumssuch as gum karaya, xanthan gum, gum arabic, and gum tragacanth can alsobe used. Colloidal magnesium aluminum silicate or finely divided silicacan be used as part of the thickening agent to further improve texture.Thickening agents can be used in an of amount from about 0.1% to about15%, by weight of the dentifrice composition.

Another optional component of the compositions desired herein is ahumectant. The humectant serves to keep toothpaste compositions fromhardening upon exposure to air and certain humectants can also impartdesirable sweetness of flavor to toothpaste compositions. Suitablehumectants for use in the invention include glycerin, sorbitol,polyethylene glycol, propylene glycol, and other edible polyhydricalcohols. The humectant generally comprises from about 0% to 70%, andpreferably from about 15% to 55%, by weight of the composition.

Water employed in the preparation of commercially suitable oralcompositions should preferably be of low ion content and free of organicimpurities. Water will generally comprise from about 5% to about 70%,and preferably from about 10% to about 50%, by weight of the compositionherein. The polymeric mineral surface active agent may require a lowerlevel of water to be stable. Generally, the level of water is up toabout 20%, preferably from about 5% to about 14%, and more preferablyfrom about 7% to about 12%, by weight of the oral composition. Theamounts of water include the free water which is added plus that whichis introduced with other materials, such as with sorbitol, silica,surfactant solutions, and/or color solutions.

The present compositions may also comprise surfactants, also commonlyreferred to as sudsing agents. Suitable surfactants are those which arereasonably stable and foam throughout a wide pH range. The surfactantmay be anionic, nonionic, amphoteric, zwitterionic, cationic, ormixtures thereof. Anionic surfactants useful herein include thewater-soluble salts of alkyl sulfates having from 8 to 20 carbon atomsin the alkyl radical (e.g., sodium alkyl sulfate) and the water-solublesalts of sulfonated monoglycerides of fatty acids having from 8 to 20carbon atoms. Sodium lauryl sulfate and sodium coconut monoglyceridesulfonates are examples of anionic surfactants of this type. Othersuitable anionic surfactants are sarcosinates, such as sodium lauroylsarcosinate, taurates, sodium lauryl sulfoacetate, sodium lauroylisethionate, sodium laureth carboxylate, and sodium dodecylbenzenesulfonate. Mixtures of anionic surfactants can also be employed.Many suitable anionic surfactants are disclosed by Agricola et al., U.S.Pat. No. 3,959,458, issued May 25, 1976. Nonionic surfactants which canbe used in the compositions of the present invention can be broadlydefined as compounds produced by the condensation of alkylene oxidegroups (hydrophilic in nature) with an organic hydrophobic compoundwhich may be aliphatic or alkyl-aromatic in nature. Examples of suitablenonionic surfactants include poloxamers (sold under trade namePluronic), polyoxyethylene, polyoxyethylene sorbitan esters (sold undertrade name Tweens), fatty alcohol ethoxylates, polyethylene oxidecondensates of alkyl phenols, products derived from the condensation ofethylene oxide with the reaction product of propylene oxide and ethylenediamine, ethylene oxide condensates of aliphatic alcohols, long chaintertiary amine oxides, long chain tertiary phosphine oxides, long chaindialkyl sulfoxides, and mixtures of such materials. The amphotericsurfactants useful in the present invention can be broadly described asderivatives of aliphatic secondary and tertiary amines in which thealiphatic radical can be a straight chain or branched and wherein one ofthe aliphatic substituents contains from about 8 to about 18 carbonatoms and one contains an anionic water-solubilizing group, e.g.,carboxylate, sulfonate, sulfate, phosphate, or phosphonate. Othersuitable amphoteric surfactants are betaines, specificallycocamidopropyl betaine. Mixtures of amphoteric surfactants can also beemployed. Many of these suitable nonionic and amphoteric surfactants aredisclosed by Gieske et al., U.S. Pat. No. 4,051,234, issued Sep. 27,1977. The present composition typically comprises one or moresurfactants each at a level of from about 0.25% to about 12%, preferablyfrom about 0.5% to about 8%, and most preferably from about 1% to about6%, by weight of the composition.

Titanium dioxide may also be added to the present composition. Titaniumdioxide is a white powder which adds opacity to the compositions.Titanium dioxide generally comprises from about 0.25% to about 5%, byweight of the composition.

Coloring agents may also be added to the present composition. Thecoloring agent may be in the form of an aqueous solution, preferably 1%coloring agent in a solution of water. Color solutions generallycomprise from about 0.01% to about 5%, by weight of the composition.

A flavor system can also be added to the compositions. Suitableflavoring components include oil of wintergreen, oil of peppermint, oilof spearmint, clove bud oil, menthol, anethole, methyl salicylate,eucalyptol, cassia, 1-menthyl acetate, sage, eugenol, parsley oil,oxanone, alpha-irisone, marjoram, lemon, orange, propenyl guaethol,cinnamon, vanillin, ethyl vanillin, heliotropine, 4-cis-heptenal,diacetyl, methyl-para-tert-butyl phenyl acetate, and mixtures thereof.Coolants may also be part of the flavor system. Preferred coolants inthe present compositions are the paramenthan carboxyamide agents such asN-ethyl-p-menthan-3-carboxamide (known commercially as “WS-3”) andmixtures thereof. A flavor system is generally used in the compositionsat levels of from about 0.001% to about 5%, by weight of thecomposition.

The present invention may also include xylitol. Xylitol is a sugaralcohol that is used as a sweetener and humectant. Xylitol may provide atherapeutic effect, such as an antibacterial or anticaries effect. Thepresent compositions typically comprise xylitol at a level from about0.01% to about 25%, preferably from about 3% to about 15%, morepreferably from about 5% to about 12%, and most preferably from about 9%to about 11%, by weight of the total composition. Alternatively, ifxylitol is used as a sweetener, it may be present at a lower level, suchas from about 0.005% to about 5%, by weight of the dentifricecomposition.

Sweetening agents can be added to the compositions. These includesaccharin, dextrose, sucrose, lactose, maltose, levulose, aspartame,sodium cyclamate, D-tryptophan, dihydrochalcones, acesulfame, andmixtures thereof. Various coloring agents may also be incorporated inthe present invention. Sweetening agents and coloring agents aregenerally used in toothpastes at levels of from about 0.005% to about5%, by weight of the composition.

The present invention may also include other agents, such asantimicrobial agents. Included among such agents are water insolublenon-cationic antimicrobial agents such as halogenated diphenyl ethers,phenolic compounds including phenol and its homologs, mono andpoly-alkyl and aromatic halophenols, resorcinol and its derivatives,bisphenolic compounds and halogenated salicylanilides, benzoic esters,and halogenated carbanilides. The water soluble antimicrobials includequaternary ammonium salts and bis-biquanide salts, among others.Triclosan monophosphate is an additional water soluble antimicrobialagent. The quaternary ammonium agents include those in which one or twoof the substitutes on the quaternary nitrogen has a carbon chain length(typically alkyl group) from about 8 to about 20, typically from about10 to about 18 carbon atoms while the remaining substitutes (typicallyalkyl or benzyl group) have a lower number of carbon atoms, such as fromabout 1 to about 7 carbon atoms, typically methyl or ethyl groups.Dodecyl trimethyl ammonium bromide, tetradecylpyridinium chloride,domiphen bromide, N-tetradecyl-4-ethyl pyridinium chloride, dodecyldimethyl (2-phenoxyethyl) ammonium bromide, benzyl dimethylstearylammonium chloride, cetyl pyridinium chloride, quaternized5-amino-1,3-bis(2-ethyl-hexyl)-5-methyl hexa hydropyrimidine,benzalkonium chloride, benzethonium chloride and methyl benzethoniumchloride are exemplary of typical quaternary ammonium antibacterialagents. Other compounds are bis[4-(R-amino)-1-pyridinium] alkanes asdisclosed in U.S. Pat. No. 4,206,215, issued Jun. 3, 1980, to Bailey.Other antimicrobials such as copper bisglycinate, copper glysinate, zinccitrate, and zinc lactate may also be included. Also useful are enzymes,including endoglycosidase, papain, dextranase, mutanase, and mixturesthereof. Such agents are disclosed in U.S. Pat. No. 2,946,725, Jul. 26,1960, to Norris et al. and in U.S. Pat. No. 4,051,234, Sep. 27, 1977 toGieske et al. Specific antimicrobial agents include chlorhexidine,triclosan, triclosan monophosphate, and flavor oils such as thymol.Triclosan and other agents of this type are disclosed in Parran, Jr. etal., U.S. Pat. No. 5,015,466, issued May 14, 1991, and U.S. Pat. No.4,894,220, Jan. 16, 1990 to Nabi et al. The water insolubleantimicrobial agents, water soluble agents, and enzymes may be presentin either the first or second dentifrice compositions. The quaternaryammonium agents, stannous salts, and substituted guanidines arepreferably present in an oral composition separate from the polymericmineral surface active agent. These agents may be present at levels offrom about 0.01% to about 1.5%, by weight of the dentifrice composition.

The oral compositions of the present invention are in the form oftoothpastes, dentifrices, topical oral gels, mouthrinses, dentureproducts, mouthsprays, lozenges, oral tablets, or chewing gums. Thedentifrice compositions may be a paste, gel, or any configuration orcombination thereof. If a dual phase formulation is used, it ispreferred that the dentifrice compositions be physically separated. Alsofor aesthetics reasons, it is preferred that one composition be a pasteand the other composition be a gel. The dispenser may be a tube, pump,or any other container suitable for dispensing toothpaste. Dualcompartment packages suitable for this purpose are described in U.S.Pat. No. 4,528,180, issued Jul. 9, 1985; U.S. Pat. No. 4,687,663, issuedAug. 18, 1987; and Pat. No. 4,849,213, issued Jul. 18, 1989, all toShaeffer. The dispenser will deliver approximately equal amounts of eachdentifrice composition through an opening. The compositions may intermixonce dispensed. Alternatively, the oral formulation may be deliveredfrom a kit containing two separate dispensers which are used to delivertwo dentifrice compositions that are both used simultaneously.

The method of use for providing immediate and sustained protectionagainst dental erosion herein comprises contacting a subject's dentalenamel surfaces and mucosa in the mouth with the oral compositionsaccording to the present invention. The method of use may be by brushingwith a dentifrice or rinsing with a dentifrice slurry or mouthrinse.Other methods include contacting the topical oral gel, dentures product,mouthspray, or other form with the subject's teeth and oral mucosa. Thesubject may be any person or lower animal whose tooth surface contactthe oral composition.

It should be understood that the present invention relates not only tomethods for delivering the present active agents containing compositionsto the oral cavity of a human, but also to methods of delivering thesecompositions to the oral cavity of other animals, e.g., household petsor other domestic animals, or animals kept in captivity.

For example, a method of use may include a person brushing a dog's teethwith one of the dentifrice compositions. Another example would includethe rinsing of a cat's mouth with an oral composition for a sufficientamount of time to see a benefit. Pet care products such as chews andtoys may be formulated to contain the present oral compositions. Thecomposition including the polymeric surface active agent is incorporatedinto a relatively supple but strong and durable material such asrawhide, ropes made from natural or synthetic fibers, and polymericarticles made from nylon, polyester or thermoplastic polyurethane. Asthe animal chews, licks or gnaws the product, the incorporated activeelements are released into the animal' s oral cavity into a salivarymedium, comparable to an effective brushing or rinsing.

EXAMPLES

The following examples further describe and demonstrate embodimentswithin the scope of the present invention. These examples are givensolely for the purpose of illustration and are not to be construed aslimitations of the present invention as many variations thereof arepossible without departing from the spirit and scope.

Example 1

-   -   The effectiveness of dentifrice compositions of the present        invention were tested according to the following in vitro        erosion cycling protocol.    -   Tooth (dentin or enamel) specimens are prepared by cutting 3mm        4mm cores from extracted, human teeth using a diamond core        drill. The teeth, collected by local surgeons, are stored until        use in a 5% Thymol solution maintained at room temperature.        Specimens are mounted on lucite rods with a dental acrylic (Dura        Base, Reliance Mfg. Co.) covering all sides except the surface.        Course polishing with 600-grit silicon carbide-water slurry is        used to remove approximately 50 microns of the outer specimen        surface to ensure homogeneity among specimens., Specimens are        then polished with gamma alumina (Buehler No. 3, B Gamma        Micropolish Alumina) to a mirror-like finish.

Portions of the surface of each specimen are then covered with an acidresistant nail polish (placed in a mesial-distal fashion), leaving atleast one uncovered strip of tooth surface exposed for treatment.Covered portions remain covered with the acid-resistant nail polishthroughout the experiment, serving as the control (untreated) areas forlater microradiographic analysis.

After placing specimens in groups of four, each group of specimens isplaced in 20 ml of fresh, pooled human saliva for at least one hour toform an initial layer of pellicle on the specimen surfaces prior tofirst day of treatment. Typical test products (dentifrice treatment A)are listed in Table 1 along with the acidic beverage (Coca Cola)challenge (Treatment B), though both the dentifrice treatments andchallenge can be modified from study to study. Other acidic beveragesused in similar studies include ginger ale, grapefruit juice, orangejuice, etc. Dentifrice slurries are prepared by mixing 5 grams ofdentifrice with 15 grams of fresh, pooled human saliva for a period ofnot less than 4 nor more than 5 minutes prior to use. A fresh slurry ofdentifrice:saliva is prepared for each treatment. After treatment withthe appropriate dentifrice slurry (1 minute exposure followed by briefrinsing with deionized, distilled water), specimens are exposed to thesaliva bath for five minutes before immersing into the acidic beveragechallenge (Treatment B) for ten minutes. Fresh beverage is used for eachtreatment. This series of treatments (A followed by saliva followed byB) is repeated 7 times a day for a total of five treatment days. Ageneral protocol is presented in Table 2. After each treatment, eachgroup of specimens is rinsed with deionized, distilled water and placedin approximately 20 ml of fresh, pooled human saliva until the time ofthe next treatment. At any time specimens are not in treatment, they areplaced in 20 ml of fresh, pooled human saliva (stirred). The specimensremain in the saliva bath overnight (stirred at room temperature).

After 5 days of treatment, thin cross-sections (80-120 μm thick) of eachspecimen are removed for assessment using standardized transversemicroradiography (TMR) techniques. The exposed, treated area of eachspecimen is assessed with respect to complete mineral loss (erosion).Results are presented in Table 3 as depth (in microns) of total mineralloss from the original specimen surface using the covered (untreated)areas as anatomical reference points.

The following example compositions were evaluated for their effect onprotecting the teeth against the erosive challenge of a commerciallyavailable carbonated soft drink, Coca Cola.

TABLE 1 Dentifrice Actives Acid Beverage Treatment A Treatment BStannous + Polyphosphate¹ Coca Cola Zinc Lactate + Polyphosphate¹ CocaCola Polyphosphate¹ Coca Cola Zinc Citrate + Polyphosphate¹ Coca ColaZinc Citrate Coca Cola Placebo Coca Cola ¹Polyphosphate is Glass Hsupplied by FMC Corp.

TABLE 2 Day 1 saliva soak(night before □12 hr) TIME treatment 1 8:00amsaliva soak treatment 2 9:00am saliva soak treatment 3 10:00am  salivasoak treatment 4 11:00pm  saliva soak treatment 5 1:00pm saliva soaktreatment 6 2:00pm saliva soak treatment 7 3:00pm saliva overnightRepeat for 5 days

TABLE 3 Dentifrice Test Product Depth of Complete Mineral LossContaining: (μm) Stannous + Polyphosphate¹ 0 Zinc Lactate +Polyphosphate¹ 0 Polyphosphate¹ 1.7 Zinc Citrate + Polyphosphate¹ 4.0Zinc Citrate 10.7 Placebo 13.9 ¹Polyphosphate is Glass H supplied by FMCCorp.

These data show that compared to no treatment, there is significantlyless loss of tooth mineral surface when the tooth was treated withdentifrice compositions containing polyphosphate, stannous and zinc ion,with no loss at all when using the combination of polyphosphate witheither zinc or stannous. These findings provide strong evidence of theprotective nature of oral compositions containing polyphosphate,stannous or zinc either alone or in combination in their ability toprotect human enamel against erosion from acidic challenge.

The sustained effects of Glass H polyphosphate in protecting the enamelsurface against erosive challenges were tested in a separate studydesign wherein groups of specimens were challenged at intervals of 5minutes, 1 hour or 2 hours post treatment in the dentifrice slurry withthe acidic beverage (Coca Cola) challenge.

An example of the result of studies demonstrating the extendedprotection afforded the tooth specimens as a result of treatment withthe dentifrice according to the present invention is included in Table4, which presents data from a 6-leg study design.

TABLE 4 Depth of Complete Mineral Loss (μm) Challenged at 5 Challengedat 1 hour Challenged at 2 hours Dentifrice Test minutes post postdentifrice post dentifrice Product Containing: dentifrice treatmenttreatment treatment Polyphosphate¹ 0.0 0.0 0.0 Control 8.5 10.5 15.9¹Polyphosphate is Glass H supplied by FMC Corp.

Example II

Formula Formula Formula Formula Formula Ingredient A B C D E Flavor1.000 1.200 1.500 1.150 0.800 Glycerin 53.166 54.300 52.872 9.000 38.519Poloxamer 407 5.000 3.000 8.000 — — Stannous Chloride 0.680 — — — —Stannous Sulfate — 1.460 — — — Stannous Fluoride 0.454 — — — 0.454 ZincLactate Dihydrate — — — — 2.500 Sodium Fluoride — 0.320 — 0.243 — SodiumMonofluorophosphate — — 1.128 — — Sodium Lauryl Sulfate^((a)) 7.5006.000 4.000 4.000 2.500 Silica 20.000 18.000 22.000 22.000 25.000Carboxymethyl Cellulose 0.200 0.200 0.400 — — Sodium Gluconate — 1.470 —— 0.652 Sodium Saccharin 0.400 0.350 0.500 0.460 0.500 Titanium Dioxide0.500 0.500 0.500 — — Xanthan Gum 0.100 0.200 0.100 0.600 0.600Carageenan — — — — 0.600 Glass H Polyphosphate 11.000 13.000 9.000 —13.000 Poly (diphosphonate/acrylate) — — — 5.000 — Na hydroxide^((b)) —— — trace — FD&C Blue #1 ^((c)) — — — — 0.025 Sorbitol ^((d)) — — —28.937 — Carbopol — — — 0.200 — Polyethylene Glycol — — — 3.000 7.000Propylene Glycol — — — — 7.000 Trisodium Phosphate — — — — 1.100 Water —— — 25.410 — ^((a))27.9% solution ^((b))50% solution ^((c)) 1% solution^((d)) 70% solution

Dentifrice compositions (Formula A-E) are prepared using conventionalmixing techniques as follows. Add the glycerin or sorbitol andthickening agents to the main mix tank and mix until homogeneous. Ifapplicable, add the sodium gluconate to the main mix tank and mix untilhomogeneous. Add the sodium lauryl sulfate solution and flavor to themain mix tank and mix until thickeners are hydrated/dissolved. Add thesilica and titanium dioxide to the main mix tank and mix untilhomogeneous. Add metal and/or fluoride salts to the main mix tank andmix until homogeneous. Finally add the polymeric mineral surface activeagent (Glass H or polyphosphonate) to the main mix tank. Mix untilhomogeneous.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application and any patent application or patent to which thisapplication claims priority or benefit thereof, is hereby herein byreference in its entirety unless expressly excluded or otherwiselimited. The citation of any document is not an admission that it isprior art with respect to any invention disclosed or claimed herein orthat it alone, or in any combination with any other reference orreferences, teaches, suggests or discloses any such invention. Further,to the extent that any meaning or definition of a term in this documentconflicts with any meaning or definition of the same term in a documentincorporated by reference, the meaning or definition assigned to thatterm in this document shall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A single-phase dentifrice composition comprising: a. a metal ion source selected from the group consisting of stannous salts, zinc salts, and combinations thereof. b. tripolyphosphate; c. a silica abrasive; d. a humectant selected from the group consisting of glycerin, sorbitol, polyethylene glycol, propylene glycol, and mixtures thereof; e. from about 0.25% to about 12%, by weight of the composition, of cocamidopropyl betaine; f. from about 0.1% to about 15%, by weight of the composition, of a thickening system selected from the group consisting of carrageenan, hydroxyethyl cellulose, sodium carboxymethylcellulose, sodium hydroxyethyl cellulose, gum karaya, xanthan gum, gum arabic, gum tragacanth, and combinations thereof; and g. from 10% to 50%, by weight of the composition, of water.
 2. The single-phase dentifrice composition of claim 1, wherein the metal ion source comprises stannous fluoride.
 3. The single-phase dentifrice composition of claim 1, wherein the composition comprises from about 0.005% to about 5%, by weight of the compositions, of a sweetening agent.
 4. The single-phase dentifrice composition of claim 2, wherein the humectant comprises glycerin.
 5. The single-phase dentifrice composition of claim 1 comprising from about 1% to about 35%, by weight of the composition, of the tripolyphosphate.
 6. The single-phase dentifrice composition of claim 2, comprising about 0.454%, by weight of the composition, of stannous fluoride.
 7. The single-phase dentifrice composition of claim 1, wherein the composition has a pH of from about 4 to about
 10. 8. The single-phase dentifrice composition of claim 1, wherein the composition comprises a peroxide source.
 9. The single-phase dentifrice composition of claim 1, wherein the thickening system comprises sodium carboxymethylcellulose.
 10. The single-phase composition of claim 1, wherein the composition comprises from about 0.25% to about 12%, by weight of the composition, of sodium lauryl sulfate.
 11. The single-phase composition of claim 1, wherein the humectant comprises glycerin and the thickening system comprises sodium carboxymethylcellulose.
 12. A single-phase dentifrice composition comprising: a. a metal ion source selected from the group consisting of stannous salts, zinc salts, and combinations thereof; b. tripolyphosphate; c. a silica abrasive; d. a humectant selected from the group consisting of glycerin, sorbitol, polyethylene glycol, propylene glycol, and mixtures thereof; e. from about 0.25% to about 12%, by weight of the composition, of sodium lauryl sulfate; f. from about 0.1% to about 15%, by weight of the composition, of a thickening system selected from the group consisting of carrageenan, hydroxyethyl cellulose, sodium carboxymethylcellulose, sodium hydroxyethyl cellulose, gum karaya, xanthan gum, gum arabic, gum tragacanth, and combinations thereof; and g. from 10% to 50%, by weight of the composition, of water.
 13. The single-phase dentifrice composition of claim 12, wherein the metal ion source comprises stannous fluoride.
 14. The single-phase dentifrice composition of claim 13, wherein the composition comprises from about 0.005% to about 5%, by weight of the composition, of a sweetening agent.
 15. The single-phase dentifrice composition of claim 13, wherein the humectant comprises glycerin.
 16. The single-phase dentifrice composition of claim 13, wherein the composition has a pH of from about 4 to about
 10. 17. The single-phase dentifrice composition of claim 13, wherein the composition comprises a peroxide source.
 18. The single-phase dentifrice composition of claim 13, wherein the thickening system comprises sodium carboxymethylcellulose.
 19. The single-phase dentifrice composition of claim 13, wherein the humectant comprises glycerin and the thickening system comprises sodium carboxymethylcellulose.
 20. The single-phase dentifrice composition of claim 19, further comprising from about 0.25% to about 12%, by weight of the composition, of cocamidopropyl betaine 